A method for making a wrench includes a step of making a mediate member, a movable jaw and an adjusting member, a step of applying heat treatment to the mediate member, the movable jaw and the adjusting member, a step of cleaning respective surfaces of the mediate member, the movable jaw and the adjusting member, and coating a anti-rusting layer on the mediate member, the movable jaw and the adjusting member, and a step of combination to put the mediate member in a mold and making a body by way of injection to integrally connect the mediate member to a head of the main body, the movable jaw and the adjusting member are installed to the body.